Re: [dpdk-dev] discussion: creating a new class for vdpa driversxiao.w.wang@intel.com

[Tiwei Bie <tiwei.bie@intel.com>]

On Fri, Dec 06, 2019 at 11:04:43AM +0100, Maxime Coquelin wrote:
> On 12/6/19 10:05 AM, Andrew Rybchenko wrote:
> > On 12/6/19 8:32 AM, Liang, Cunming wrote:
> >>> -----Original Message-----
> >>> From: Bie, Tiwei <tiwei.bie@intel.com>
> >>> Sent: Friday, December 6, 2019 12:28 PM
> >>> To: Matan Azrad <matan@mellanox.com>
> >>> Cc: Wang, Xiao W <xiao.w.wang@intel.com>; Thomas Monjalon
> >>> <thomas@monjalon.net>; maxime.coquelin@redhat.com; Wang, Zhihong
> >>> <zhihong.wang@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>; Shahaf Shuler
> >>> <shahafs@mellanox.com>; Ori Kam <orika@mellanox.com>; dev@dpdk.org; Slava
> >>> Ovsiienko <viacheslavo@mellanox.com>; Asaf Penso <asafp@mellanox.com>; Olga
> >>> Shern <olgas@mellanox.com>; Liang, Cunming <cunming.liang@intel.com>
> >>> Subject: Re: discussion: creating a new class for vdpa
> >>> driversxiao.w.wang@intel.com
> >>>
> >>> On Thu, Dec 05, 2019 at 01:26:36PM +0000, Matan Azrad wrote:
> >>>> Hi all
> >>>>
> >>>> As described in RFC “[RFC] net: new vdpa PMD for Mellanox devices”, a
> >>>> new vdpa drivers is going to be added for Mellanox devices – mlx5_vdpa
> >>>>
> >>>> The only vdpa driver now is the IFC driver that is located in net directory.
> >>>>
> >>>> The IFC driver and the new mlx5_vdpa driver provide the vdpa ops and
> >>>> not the eth_dev ops.
> >>>>
> >>>> All the others drivers in net provide the eth-dev ops.
> >>>>
> >>>> I suggest to create a new class for vdpa drivers, to move IFC to this
> >>>> class and to add the mlx5_vdpa to this class too.
> >>>>
> >>>> Later, all the new drivers that implements the vdpa ops will be added
> >>>> to the vdpa class.
> >>>
> >>> +1. Sounds like a good idea to me.
> >> +1
> > 
> > vDPA drivers are vendor-specific and expected to talk to vendor
> > NIC. I.e. there are significant chances to share code with
> > network drivers (e.g. base driver). Should base driver be moved
> > to drivers/common in this case or is it still allows to have
> > vdpa driver in drivers/net together with ethdev driver?
> > 
> 
> That's a good point.
> 
> For example, for the Virtio vDPA driver, I placed it in th Virtio PMD
> directory, so that we can re-use the Virtio-pci layer.
> On the other hand, for the specific Virtio case, it may be preferable
> to have a common directory. Doing that, the Virtio-pci layer could be
> reused by Virtio PMD, Virtio vDPA, but also Virtio Crypto drivers.

For the virtio case, I also prefer to have a common directory
to allow different virtio drivers to share the virtio-pci layer.

Thanks,
Tiwei

> 
> I plan to submit again my Virtio vDPA next week as it didn't make it in
> v19.11. I'll wait for an agreement on this topic before proceeding.
> 
> Thanks,
> Maxime
>